1 files changed, 262 insertions, 0 deletions
diff --git a/src/core/lib/channel/channel_stack.cc b/src/core/lib/channel/channel_stack.cc
new file mode 100644
index 0000000000..775c8bc667
--- /dev/null
+++ b/src/core/lib/channel/channel_stack.cc
@@ -0,0 +1,262 @@
+/*
+ *
+ * Copyright 2015 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#include "src/core/lib/channel/channel_stack.h"
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+
+#include <stdlib.h>
+#include <string.h>
+
+grpc_tracer_flag grpc_trace_channel = GRPC_TRACER_INITIALIZER(false, "channel");
+
+/* Memory layouts.
+
+   Channel stack is laid out as: {
+     grpc_channel_stack stk;
+     padding to GPR_MAX_ALIGNMENT
+     grpc_channel_element[stk.count];
+     per-filter memory, aligned to GPR_MAX_ALIGNMENT
+   }
+
+   Call stack is laid out as: {
+     grpc_call_stack stk;
+     padding to GPR_MAX_ALIGNMENT
+     grpc_call_element[stk.count];
+     per-filter memory, aligned to GPR_MAX_ALIGNMENT
+   } */
+
+/* Given a size, round up to the next multiple of sizeof(void*) */
+#define ROUND_UP_TO_ALIGNMENT_SIZE(x) \
+  (((x) + GPR_MAX_ALIGNMENT - 1u) & ~(GPR_MAX_ALIGNMENT - 1u))
+
+size_t grpc_channel_stack_size(const grpc_channel_filter **filters,
+                               size_t filter_count) {
+  /* always need the header, and size for the channel elements */
+  size_t size =
+      ROUND_UP_TO_ALIGNMENT_SIZE(sizeof(grpc_channel_stack)) +
+      ROUND_UP_TO_ALIGNMENT_SIZE(filter_count * sizeof(grpc_channel_element));
+  size_t i;
+
+  GPR_ASSERT((GPR_MAX_ALIGNMENT & (GPR_MAX_ALIGNMENT - 1)) == 0 &&
+             "GPR_MAX_ALIGNMENT must be a power of two");
+
+  /* add the size for each filter */
+  for (i = 0; i < filter_count; i++) {
+    size += ROUND_UP_TO_ALIGNMENT_SIZE(filters[i]->sizeof_channel_data);
+  }
+
+  return size;
+}
+
+#define CHANNEL_ELEMS_FROM_STACK(stk)                                   \
+  ((grpc_channel_element *)((char *)(stk) + ROUND_UP_TO_ALIGNMENT_SIZE( \
+                                                sizeof(grpc_channel_stack))))
+
+#define CALL_ELEMS_FROM_STACK(stk)       \
+  ((grpc_call_element *)((char *)(stk) + \
+                         ROUND_UP_TO_ALIGNMENT_SIZE(sizeof(grpc_call_stack))))
+
+grpc_channel_element *grpc_channel_stack_element(
+    grpc_channel_stack *channel_stack, size_t index) {
+  return CHANNEL_ELEMS_FROM_STACK(channel_stack) + index;
+}
+
+grpc_channel_element *grpc_channel_stack_last_element(
+    grpc_channel_stack *channel_stack) {
+  return grpc_channel_stack_element(channel_stack, channel_stack->count - 1);
+}
+
+grpc_call_element *grpc_call_stack_element(grpc_call_stack *call_stack,
+                                           size_t index) {
+  return CALL_ELEMS_FROM_STACK(call_stack) + index;
+}
+
+grpc_error *grpc_channel_stack_init(
+    grpc_exec_ctx *exec_ctx, int initial_refs, grpc_iomgr_cb_func destroy,
+    void *destroy_arg, const grpc_channel_filter **filters, size_t filter_count,
+    const grpc_channel_args *channel_args, grpc_transport *optional_transport,
+    const char *name, grpc_channel_stack *stack) {
+  size_t call_size =
+      ROUND_UP_TO_ALIGNMENT_SIZE(sizeof(grpc_call_stack)) +
+      ROUND_UP_TO_ALIGNMENT_SIZE(filter_count * sizeof(grpc_call_element));
+  grpc_channel_element *elems;
+  grpc_channel_element_args args;
+  char *user_data;
+  size_t i;
+
+  stack->count = filter_count;
+  GRPC_STREAM_REF_INIT(&stack->refcount, initial_refs, destroy, destroy_arg,
+                       name);
+  elems = CHANNEL_ELEMS_FROM_STACK(stack);
+  user_data =
+      ((char *)elems) +
+      ROUND_UP_TO_ALIGNMENT_SIZE(filter_count * sizeof(grpc_channel_element));
+
+  /* init per-filter data */
+  grpc_error *first_error = GRPC_ERROR_NONE;
+  for (i = 0; i < filter_count; i++) {
+    args.channel_stack = stack;
+    args.channel_args = channel_args;
+    args.optional_transport = optional_transport;
+    args.is_first = i == 0;
+    args.is_last = i == (filter_count - 1);
+    elems[i].filter = filters[i];
+    elems[i].channel_data = user_data;
+    grpc_error *error =
+        elems[i].filter->init_channel_elem(exec_ctx, &elems[i], &args);
+    if (error != GRPC_ERROR_NONE) {
+      if (first_error == GRPC_ERROR_NONE) {
+        first_error = error;
+      } else {
+        GRPC_ERROR_UNREF(error);
+      }
+    }
+    user_data += ROUND_UP_TO_ALIGNMENT_SIZE(filters[i]->sizeof_channel_data);
+    call_size += ROUND_UP_TO_ALIGNMENT_SIZE(filters[i]->sizeof_call_data);
+  }
+
+  GPR_ASSERT(user_data > (char *)stack);
+  GPR_ASSERT((uintptr_t)(user_data - (char *)stack) ==
+             grpc_channel_stack_size(filters, filter_count));
+
+  stack->call_stack_size = call_size;
+  return first_error;
+}
+
+void grpc_channel_stack_destroy(grpc_exec_ctx *exec_ctx,
+                                grpc_channel_stack *stack) {
+  grpc_channel_element *channel_elems = CHANNEL_ELEMS_FROM_STACK(stack);
+  size_t count = stack->count;
+  size_t i;
+
+  /* destroy per-filter data */
+  for (i = 0; i < count; i++) {
+    channel_elems[i].filter->destroy_channel_elem(exec_ctx, &channel_elems[i]);
+  }
+}
+
+grpc_error *grpc_call_stack_init(grpc_exec_ctx *exec_ctx,
+                                 grpc_channel_stack *channel_stack,
+                                 int initial_refs, grpc_iomgr_cb_func destroy,
+                                 void *destroy_arg,
+                                 const grpc_call_element_args *elem_args) {
+  grpc_channel_element *channel_elems = CHANNEL_ELEMS_FROM_STACK(channel_stack);
+  size_t count = channel_stack->count;
+  grpc_call_element *call_elems;
+  char *user_data;
+  size_t i;
+
+  elem_args->call_stack->count = count;
+  GRPC_STREAM_REF_INIT(&elem_args->call_stack->refcount, initial_refs, destroy,
+                       destroy_arg, "CALL_STACK");
+  call_elems = CALL_ELEMS_FROM_STACK(elem_args->call_stack);
+  user_data = ((char *)call_elems) +
+              ROUND_UP_TO_ALIGNMENT_SIZE(count * sizeof(grpc_call_element));
+
+  /* init per-filter data */
+  grpc_error *first_error = GRPC_ERROR_NONE;
+  for (i = 0; i < count; i++) {
+    call_elems[i].filter = channel_elems[i].filter;
+    call_elems[i].channel_data = channel_elems[i].channel_data;
+    call_elems[i].call_data = user_data;
+    grpc_error *error = call_elems[i].filter->init_call_elem(
+        exec_ctx, &call_elems[i], elem_args);
+    if (error != GRPC_ERROR_NONE) {
+      if (first_error == GRPC_ERROR_NONE) {
+        first_error = error;
+      } else {
+        GRPC_ERROR_UNREF(error);
+      }
+    }
+    user_data +=
+        ROUND_UP_TO_ALIGNMENT_SIZE(call_elems[i].filter->sizeof_call_data);
+  }
+  return first_error;
+}
+
+void grpc_call_stack_set_pollset_or_pollset_set(grpc_exec_ctx *exec_ctx,
+                                                grpc_call_stack *call_stack,
+                                                grpc_polling_entity *pollent) {
+  size_t count = call_stack->count;
+  grpc_call_element *call_elems;
+  char *user_data;
+  size_t i;
+
+  call_elems = CALL_ELEMS_FROM_STACK(call_stack);
+  user_data = ((char *)call_elems) +
+              ROUND_UP_TO_ALIGNMENT_SIZE(count * sizeof(grpc_call_element));
+
+  /* init per-filter data */
+  for (i = 0; i < count; i++) {
+    call_elems[i].filter->set_pollset_or_pollset_set(exec_ctx, &call_elems[i],
+                                                     pollent);
+    user_data +=
+        ROUND_UP_TO_ALIGNMENT_SIZE(call_elems[i].filter->sizeof_call_data);
+  }
+}
+
+void grpc_call_stack_ignore_set_pollset_or_pollset_set(
+    grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
+    grpc_polling_entity *pollent) {}
+
+void grpc_call_stack_destroy(grpc_exec_ctx *exec_ctx, grpc_call_stack *stack,
+                             const grpc_call_final_info *final_info,
+                             grpc_closure *then_schedule_closure) {
+  grpc_call_element *elems = CALL_ELEMS_FROM_STACK(stack);
+  size_t count = stack->count;
+  size_t i;
+
+  /* destroy per-filter data */
+  for (i = 0; i < count; i++) {
+    elems[i].filter->destroy_call_elem(
+        exec_ctx, &elems[i], final_info,
+        i == count - 1 ? then_schedule_closure : NULL);
+  }
+}
+
+void grpc_call_next_op(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
+                       grpc_transport_stream_op_batch *op) {
+  grpc_call_element *next_elem = elem + 1;
+  GRPC_CALL_LOG_OP(GPR_INFO, next_elem, op);
+  next_elem->filter->start_transport_stream_op_batch(exec_ctx, next_elem, op);
+}
+
+void grpc_channel_next_get_info(grpc_exec_ctx *exec_ctx,
+                                grpc_channel_element *elem,
+                                const grpc_channel_info *channel_info) {
+  grpc_channel_element *next_elem = elem + 1;
+  next_elem->filter->get_channel_info(exec_ctx, next_elem, channel_info);
+}
+
+void grpc_channel_next_op(grpc_exec_ctx *exec_ctx, grpc_channel_element *elem,
+                          grpc_transport_op *op) {
+  grpc_channel_element *next_elem = elem + 1;
+  next_elem->filter->start_transport_op(exec_ctx, next_elem, op);
+}
+
+grpc_channel_stack *grpc_channel_stack_from_top_element(
+    grpc_channel_element *elem) {
+  return (grpc_channel_stack *)((char *)(elem)-ROUND_UP_TO_ALIGNMENT_SIZE(
+      sizeof(grpc_channel_stack)));
+}
+
+grpc_call_stack *grpc_call_stack_from_top_element(grpc_call_element *elem) {
+  return (grpc_call_stack *)((char *)(elem)-ROUND_UP_TO_ALIGNMENT_SIZE(
+      sizeof(grpc_call_stack)));
+}